A router network using TCP/IP includes network routing controllers controlling information transmission paths in a network, and network management apparatuses managing the network routing controllers are known. Also, in a router network, a network routing controller dynamically changes a routing table which is used in routing control with the use of a routing protocol is known.    [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2000-22734    [Patent Document 2] Japanese Patent No. 4131263
A plurality of partitions can be set in a network, and a node in the network can be assigned to any of the partitions. In such a case, if a routing table is mistakenly updated, another partition might be affected depending on an aspect of an error.